1. Field of the Invention
The present invention relates to piezoelectric devices and, more particularly, to piezoelectric motors.
2. Description of the Prior Art
Known in the art is a piezoelectric motor (GB,A, 2118374B), comprising a stator, a rotor frictionally interacting with the stator having a housing, a piezoelectric oscillator producing radial mode vibrations mounted on the housing and comprising a piezoelectric cell disposed coaxially with the rotor and made in the form of a disk with electrodes, the disk being polarized perpendicular to the electrodes, and at least two pushers, each pusher having one end secured on the cylindrical surface of the piezoelectric cell and another end resting against the rotor.
In this piezoelectric motor any change of the rotational speed can be effected only by changing the diameter of the piezoelectric cell. This does not allow one to make a general-purpose piezoelectric cell suitable for any rotational speed of the rotor of the piezoelectric cell suitable for any rotational speed of the rotor of the piezoelectric motor. Therefore, the range of rotational speeds of the rotor for a given piezoelectric cell is limited.
Furthermore, the robustness of the pusher increases with the increase in the thickness of the piezoelectric cell and this does not allow one to reduce the input power, for example, when running the piezoelectric motor under a low load, e.g. for driving the diaphragm of a photographic camera.